1. Field of the Invention
The present invention relates to a fluorescent lamp with greater efficacy than conventional fluorescent lamps with circular cross-section. The application of magnetic fields spreads the arc throughout the larger volume of the lamp envelope.
2. Description of Prior Art
The present invention applies the technique of magnetic arc spreading coils described in the copending patent applications, Ser. Nos. 093053 and 45589 to straight line fluorescent lamps for use in fixtures, ceiling mounted or otherwise. The use of the magnetic field generated by the arc spreading coils permits lamps to be constructed with other than circular cross-section. Thus, such lamps have greater surface area with more phosphor surface activated. Lamps with arc spreading have greater efficacy than conventional fluorescent lamps with circular cross-section. However, atmospheric pressure on non-circular cross-section shaped evacuated lamp envelopes is so great that commercially feasible lamp envelopes cannot be mass produced that will not collapse inwardly except by production methods involving prohibitive cost.